Paper manufacture



Patented Jan. 19, 1937 PATENT OFFICE PAPER. MANUFACTURE Raymond F. Rainier, Lakewood, Ohio, assignor, by mesne assignments, to E. I. du Pont de Nemours & Company. poration oi Delaware No Drawing.

Claims.

This invention relates to the cooking of fibrous materials, such as straw, grass, corn stalks, bagasse, and wood chips excluding resinous woods, for the production of pulp suitable for use in the 5 manufacture of paper and the like, and isparticularly directed to such cooking processes wherein the action of the cooking medium is modified by the addition of an introfier.

In the production of a pulp suitable for use in has been the practice to subject fibrous materials suchas straw, grass, bagasse, wood chips other than resinous wood, and the like, to the action of an alkaline cooking medium. The cooking medium acts to render undesired constituents soluble, and to free the fibers so that they may be utilized in the manufacture of paper and the like. The cooking is usually carried out at relatively high temperatures and pressures in order to shorten the time required to soften the fibrous material and to bring it to the desired condition.

I have found that the addition of a small amount of an introfier to the alkaline cooking medium increases its rate of penetration and very materially shortens the time required to bring the fibrous material to the desired condition. The introfier also decreases the amount of alkali required for cooking and decreases the amount Y of washing that the pulp requires. The employpulp, and results in the quality of the fiber beinggc much improved. v

I have studied the effects of a. large number of substances as introfiers for alkaline cooking media, and the following are among the best:

the manufacture of paper, fiber board, etc. it

,ment of an introfier results in a more uniform Wilmington, DeL, a cor- Application November 5, 1934. Serial No. 7512583 My empirical results show that the most marked improvement in the properties of an alkaline cooking medium results when a material selected from the group consisting of turpentine, chloroform, lauryl alcohol, methyl cyclohexanol, perchlorethylene, and pyridine, is used as an introfier. This group of materials, therefore, includes my preferred materials.

I especially prefer to use turpentine. It is cheap and non-toxic. It is soluble enough so that no difficulty is experienced in keeping an adequate amount in solution in alkaline media.

Turpentine has a boiling point of one-hundred and fifty degrees centigrade, or higher, and consequently it is not evaporated, but remains in the cooking media at the relatively high cooking temperatures.

Turpentine, moreover, exhibits great activity as an introfier for alkaline cooking media. An alkaline cooking medium is much improved by the addition of a small amount of turpentine: less of the cooking medium is required for a given quantity of fibrous material, a shorter time is required to bring the fibrous material to thedesired condition, and the pulp obtained is of a more uniform and higher quality.

The quantity of introfier used may be widely varied. With materials, such as turpentine, which are only slightly soluble, it is desirable to use no more than will dissolve in the cooking medium. In any event, no particularly large amount of introfier need be added. Specifically, in the event straw is to be treated, I prefer to use about two to seven pounds of turpentine per ton of straw treated. This amounts to adding about one-half to two pounds of turpentine to each one-hundred gallons of alkaline cooking medium, assuming that about one and six-tenths pounds of medium are used for each pound of straw at the start of the cook. When other introfiers are used, I prefer to use an amount corresponding to the amount of turpentine needed. Similar amounts of introfier are used when other materials than straw are treated.

The principles of my invention may be applied to numerous processes for cooking straw and the like with gratifying results. The addition of an introfier to the alkaline cooking medium of a soda process, a sulfate process, or a process employing lime as a cooking medium leads to very satisfactory results. 7

For cooking straw I prefer to use an alkaline medium containing lime, sodium hydroxide and sodium. sulfide, or mixtures of lime and sodium hydroxide and sodium sulfide, and I prefer to use e little turpentine ee nn intranet tn euch n1? i I 1-: media.

2 I have eeirtein illustrative com positions u nreeesees eheve, K tie net intend te he iteii thereby, the scene of my invention eppeg item the teiiewinn einimn i. In e process of cooking e nitrous met, the step comprising subject: the materiel to the nation of en sine 1.; and e not amount of turpentine 2., In n pi'ecese of eeeking etrew u the like, the step compg digest etrnw with an alkaline medium which e not aunt of i: f ther.

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